DEFORMATION BEHAVIOR OF A CRYOMILLED NANOSTRUCTURED AL-7.5MG ALLOY

摘要

Mechanical behavior studies of nanostructured Al-7.5%Mg alloys with grain sizes of approximately 100 nm, processed by cryomilling and consolidation, were carried out both in liquid nitrogen and at ambient temperatures. A high yield stress and a low ductility were observed in tension in liquid nitrogen while a good ductility in liquid nitrogen was observed in compression. The compressive sample failed catastrophically at room temperature. A processing defect, a crack, was observed in the as-extruded material. Deformation twinning was not observed during plastic deformation in liquid nitrogen of the nanostructured Al-7.5%Mg alloy. The high strength of the nanostructured Al-7.5%Mg alloy was attributed to a grain size effect, solid solution strengthening, dispersion strengthening, as well as temperature dependence.